With stylish, short hair and intense green eyes, Marianne answers the door of her Washington, D.C., home wearing all black, looking like she's stepped out of the pages of a fashion magazine.
For the past five years, Marianne tells us, she has practiced the Sugar Busters! diet (no white food—sugar, flour, rice, potatoes). The only carbohydrates she eats are whole grain. Two mornings a week she wakes at 6:30, has a cup of coffee, then joins a neighbor for an hour-long brisk walk; two other mornings she works out with a trainer. She always has protein for breakfast (a poached egg or cheese on whole wheat toast)—and again with a salad for lunch. So far, so good. Then at 2, or 4, or 6—or all three—Marianne, who runs a successful business strategy firm called Larkspur Marketing from home, starts picking from a bowl of nuts or fruit, sometimes both. Shortly after 8, she and her husband, a radiologist, eat dinner together—usually salad, protein (fish, chicken, or a lean red meat), and sometimes brown rice. But afterward, "if we sit around the kitchen talking," she says, "we'll start eating other things. Even though it's all healthy, we don't have to eat after dinner. I used to be more disciplined about that."
Wansink asks Marianne what her life was like before she adopted her regimen. Marianne laughs. "I have two children. One is turning 20 and one is 25. When I was pregnant with the first, I worked at an office and ate steak and cheese sandwiches every day from a greasy grill downstairs." She exercised only sporadically until her husband began to prod her, pointing out that her bones would suffer if she didn't get active.
Wansink's advice: Despite Marianne's healthy-sounding diet, Wansink and Haven are concerned that she's not getting enough calcium. "Yogurt with muesli might curb cravings that lead you to nuts," he offers. "Even a latte instead of coffee—with fat-free milk—would be good." Ideally, she would add a cup of low-fat milk daily, but rather than buying it by the gallon, Wansink suggests the eight-ounce-carton size. "On average, a person eats or drinks 92 percent of what they serve themselves," he says, quoting another of his studies. "So if she opens that container to have a sip, she'll drink most of it by the end of the day."
Second, although nuts are good for her, Marianne is consuming too many of them. "They are one of the most energy-dense foods there is," says Wansink. "Before you know it, you've eaten hundreds of calories." He suggests that, rather than buying a big bag that she pours into a bowl, Marianne choose smaller packages, or make her own 100-calorie pouches. Based on his findings, Wansink predicts that she could reduce her nut habit by up to 27 percent. Another strategy is what he calls the pistachio principle. Given the same number of nuts (walnuts, peanuts, pistachios), people eat 45 percent less when they have to remove the shell. Wansink's final recommendation is to close the kitchen at night. Shut off the lights. Move to a different room to chat. "In our preliminary research, people who come home from work and walk through the kitchen claim to be bigger snackers than those who don't," he explains.
Two weeks later: The nuts are almost eliminated from Marianne's diet, and the kitchen is now off-limits at night; she hasn't done nearly as well with calcium. "I really wanted to reduce the nuts and stop eating after dinner. Increasing the calcium isn't something I've latched on to," she says, noting that her bone density tests are normal. Still, she has added more milk to her coffee and tried the yogurt with granola. "Maybe I will work my way up to the calcium," she says. "I know I feel better psychologically. And I feel better going to sleep without eating throughout the evening. This was a really good mind-set change."
Sarah Wildman lives in Washington, D.C., and writes for The New York Times and The Guardian, among other publications.